I can tell you what I know from the beta.
The proposed guildmaster has to buy a "charter" in one of the capital cities (there is a vendor on the lower ring near the bank in Undercity) for 10 silver pieces. Once the GM has the charter, he needs to get 9 other people on seperate accounts to "sign" the charter. Once there are 9 signatures, then the guild is created. You don't need to have all members on at once, but you do need to get the GM to get all the signatures in person.
In all, it's probably the easiest guild creation system I have ever participated in.